This invention is directed to safe rooms or tornado shelters conforming to the xe2x80x9cNational Performance Criteria for Tornado Shelters,xe2x80x9d 1st Edition, May 8, 1999, published by the Federal Emergency Management Agency (FEMA), and Booklet #320 entitled xe2x80x9cTaking Shelter From The Storm: Building a Safe Room Inside Your House,xe2x80x9d 2nd Edition, August 1999 also published by Federal Emergency Management Agency (FEMA). The criteria of these publication requires, among other things, that the shelter and components withstand forces imposed by 250 mph ground-level wind speeds and prevent perforation by a 15 lb. 2xc3x974 board traveling at a speed of 100 miles per hour. More particularly, this invention is directed to the problems of design and installation of a storm shelter meeting FEMA criteria and simultaneously being capable of efficient installation within an existing building with minimum costs of components and assembly.
This invention includes a unique door construction for completion of the shelter that is wheel chair accessible, swings inwardly to avoid being blocked by debris and has a simple actuator for a three bolt lock that facilitates operation by children. This door also meets the FEMA criteria of withstanding forces imposed by a 250 mph ground level wind and perforation by a 15 lb. 2xc3x974 board traveling at a speed of 100 miles per hour.
The problems of installing a vault or safe room facility within an existing building have been previously noted in the art. For example, U.S. Pat. No. 5,813,174 (Waller) recognized that such units often could not be installed without demolishing a major part of a building. For this reason, he disclosed a unit that could be shipped in a compact packaging unit for installation in a building without major modifications to the existing structure. While his concepts have merit, they do require special pre-fabricated xe2x80x9cconnector sleevesxe2x80x9d and xe2x80x9cwelded plate connectorsxe2x80x9d which must be welded to connection members. In addition, U.S. Pat. No. 5,813,174 teaches a xe2x80x9clight-weightxe2x80x9d steel structure and does not disclose a door structure. Importantly, since the door structure has a substantial surface area, its design, in a manner capable of meeting the FEMA guidelines, presents a challenge.
Accordingly, the present invention seeks to eliminate the need for any special pre-fabricated connectors or connections, to use heavy, 10 gauge steel, to utilize standard, off the shelf connectors and to provide a door design that will meet the standards of FEMA.
Tis invention comprises a tornado shelter that will meet the performance criteria of FEMA and withstand forces imposed by a 250 mph ground level wind as well as perforation by a 15 lb. 2xc3x974 board traveling at a speed of 100 miles per hour. It includes C-shaped channel members formed of steel and bolted together to define square or rectangular building having a door that is also capable of withstanding the same forces. Importantly, the unit is wheelchair accessible. In addition, its door locking structure reduces the risk of children locking themselves within the structure.
Accordingly, the objectives of this invention are to provide, among other things,
1) A low cost tornado shelter that requires no special prefabricated parts and may be assembled by a home owner within a room of his existing home;
2) A low cost tornado shelter having surface panel members formed to have integral interconnection capabilities and a very high substantial, integral strength;
3) A low cost tornado shelter having a wide, high strength door and assembly that does not impede wheelchair entry, opens inwardly to prevent blockage by storm debris, has a simplistic locking device and is sufficiently strong to meet FEMA criteria;
4) Surface panel members for tornado shelters formed of C-shaped construction providing ease of assembly;
5) A low cost tornado shelter that can be assembled from the inside, i.e., easily assembled within a closet of a home;
6) A low cost tornado shelter that can be disassembled from the inside so as to permit an emergency egress by disassembling any of the individual wall panels;
7) A low cost tornado shelter that does not require a separate, integrated frame structure; and
8) A door and simplified lock system that also meets the FEMA standards and is prefabricated in a manner to facilitate construction of the shelter.